scholarly journals Effect of CaO on Phase Composition and Properties of Aluminates for Barium Tungsten Cathode

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1380 ◽  
Author(s):  
Jinglin Li ◽  
Jianjun Wei ◽  
Yongbao Feng ◽  
Xiaoyun Li
Keyword(s):  
Single Phase ◽  
Emission Current Density ◽  
Environmental Stability ◽  
Precipitation Method ◽  
Pulse Emission ◽  
Molar Amount ◽  
Mixture Phase ◽  
Before And After ◽  
Method Effects ◽  
Co Precipitation

6BaO·xCaO·2Al2O3 (x = 0.8, 1.2, 1.6, 2, and 2.2) aluminates were synthesized via a liquid phase co-precipitation method. Effects of the molar amount of CaO on the phase of aluminates before and after melting and their hygroscopic phase, melting properties, environmental stability, evaporation, and emission properties were systematically studied. The results show that with the increase of the molar amount of CaO, the aluminates change from a mixture phase to a single phase of Ba3CaAl2O7, and the diffraction peak shifts to a higher angle. The melted phase of the aluminates changed from a single phase to a mixed phase of Ba5CaAl4O12 and Ba3CaAl2O7. Meanwhile, the comprehensive properties of the aluminates are improved. The weight gain of 6BaO·2CaO·2Al2O3 aluminates is only 10.88% after exposure to air for 48 h; the pulse emission current density of barium tungsten cathodes impregnated with 6BaO·2CaO·2Al2O3 aluminates in the porous tungsten matrix can reach 28.60 A/cm2 at 1050 °C, and the evaporation rate is 2.52 × 10−10 g/(cm2·s).

Preparation and Microanalysis Study of Nano-Hap/Cs-Chs Composites Materials

2012 ◽  
Vol 581-582 ◽  
pp. 463-466 ◽  
Author(s):  
Man De Qiu ◽  
Xiao Yan Wang ◽  
Yong Qing Zhai ◽  
Zi Hua Yao
Keyword(s):  
Chondroitin Sulfate ◽  
Organic Phase ◽  
Nano Particles ◽  
Precipitation Method ◽  
Composites Materials ◽  
Before And After ◽  
Calcium And Phosphorus ◽  
Co Precipitation

Nano-hydroxyapatite/chitosan-chondroitin sulfate composites materials with different weight ratios were prepared through liquid co-precipitation method. The nano-Hap、Hap/Cs and Hap/Cs-Chs composites materials under the same conditions preparation materials were researched By XRD, SEM and EDS respectively. The results show that nano-Hap particles with poorly crystallinity, the size is about 20nm, nano-Hap particles are spherical in sHape and dispersed uniformly, combined with relatively loose between particles, the small nano-particles aggregate into larger particles when the Hap composite with the Cs and Chs, nano-Hap were dispersed uniformly in the organic phase Cs and Chs, Hap particles have the trend to grow large in composites materials,crystal become more perfect, combination become relatively dense between particles, The composites materials were annealed at 700°C,Hap crystal particles become more perfect clear and larger with relatively loose between particles.EDS analysis showed that the compound before and after annealing of the material ratio of calcium had no influence, material does not contain any impurities,The ratio of calcium and phosphorus is about 1.75:1,Hap belonging to the type of calcium-rich

scholarly journals Effect of Sintering Temperature on the Microstructure, Electrical and Magnetotransport Properties of La0.67Sr0.33MnO3 Compound

2014 ◽  
Vol 895 ◽  
pp. 319-322
Author(s):  
Lim Kean Pah ◽  
Abdul Halim Shaari ◽  
Chen Soo Kien ◽  
Chin Hui Wei ◽  
Albert Gan ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
Sintering Temperature ◽  
Measurement Range ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Metal Insulator ◽  
Higher Temperature ◽  
Co Precipitation ◽  
Grain Surface

In this work, we report the effect of sintering temperature (900°C, 1000°C, 1100°C and 1200°C) on the electrical and magnetotransport properties of polycrystalline La0.67Sr0.33MnO3 (LSMO). Single phase of LSMO hexagonal structure (R-3c) accompanied with minor phases was successfully synthesized by co-precipitation method. With increasing sintering temperature, grain growth was promoted and grain connectivity was improved. It was found that an enhancement of resistivity on smaller grain size was due to larger grain surface over volume (grain boundaries effect). The shifting of the metal-insulator transition (TMI) to higher temperature was also responsible for observed changes in physical properties. TMI of 900°C, 1000°C and 1100°C were 232 K, 278 K and 298 K respectively however 1200°C was out of measurement range (higher than 300 K). In summary, CP900 with smaller grain size distribution (~200 nm) displayed the highest resistivity and MR% of -19.2% (at 80 K, 10 kG).

Synthesis and Characterization of Nanopraticle Hematite (α-Fe2O3) Minerals from Natural Iron Sand Using Co-Precipitation Method and its Potential Applications as Extrinsic Semiconductor Materials Type-N

2019 ◽  
Vol 967 ◽  
pp. 259-266 ◽  
Author(s):  
Muhammad Rizal Fahlepy ◽  
Yuyu Wahyuni ◽  
Muhamma Andhika ◽  
Arini Tiwow Vistarani ◽  
Subaer
Keyword(s):  
Ammonium Hydroxide ◽  
Raw Material ◽  
Semiconductor Materials ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Sem Image ◽  
Natural Iron ◽  
Before And After ◽  
Potential Applications ◽  
Co Precipitation

This research is about nanoparticles hematite (NPH) synthesized and characterized from natural iron sands using co-precipitation method and its potential applications as extrinsic semiconductor materials type-N. The aims of this study is to determine the process parameters to obtain hematite of high purity degree and to observe its physical characteristics as an extrinsic semiconductor materials type-N. The iron sand was first separated by magnetic technique and then dissolved into HCl solution before conducting the precipitation process. Precipitation was done by dripping ammonium hydroxide (NH4OH). Precipitated powder was dried at 80°C for 2 hours, and then calcined at 500°C, 600°C 700°C for 2 hours respectively. The composition of iron sands, purity degree, hematite mineral grain size, and space group were analyzed by XRF, XRD, FTIR and SEM. The XRF analysis result of raw material, showed that dominant element and composition in the sample is Fe with purity degree is 90.51%. The XRD result before and after precipitation showed Fe3O4 and α-Fe2O3. Fe3O4 purity degree was obtained 85%, and α-Fe2O3 in NPH500, NPH600, NPH700 were 63%, 83%, and 76%, respectively. FTIR spectral showed crystalline hematite characteristics stong band of 472.07 to 559.62 cm-1. SEM image showed the morphology of agglomeration particulates, when the calcinaton temperature increases, the agglomeration will be seperated due to thermal energy. Based on the charaterization results it was found that the natural iron sand synthesized has the potential to be applied as an N-type extrinsic semiconductor material.

Physical and Optical Properties of Indium Oxide: Tin Nanoparticles Synthesized by Co-Precipitation Method

2015 ◽  
Vol 659 ◽  
pp. 604-608 ◽  
Author(s):  
Jiruntanin Kanoksinwuttipong ◽  
Wisanu Pecharapa ◽  
Russameeruk Noonuruk ◽  
Wicharn Techitdheera
Keyword(s):  
Optical Properties ◽  
Single Phase ◽  
Precipitation Method ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Optical Absorbance ◽  
Molar Ratios ◽  
Tin Nanoparticles ◽  
Ion Substitution ◽  
Co Precipitation

Indium oxide:tin nanoparticles were synthesized by co-precipitation method using InCl3 and SnCl4·5H2O as starting precursor with different molar ratios of Sn:In. The crystalline structure, optical properties, chemical bonding and morphologies of all samples were characterized by X-ray diffraction (XRD), UV–vis spectrometer, Raman spectroscopy and field emission scanning electron microscope, respectively. The XRD results show that the crystallinity of as-synthesized powders was initially amorphous phase. After calcination at 400 °C for 2 h, a single phase ITO powder with 10% (mol%) SnO2 was obtained. The particle size of each sample is approximately 20-25 nm. The color of indium oxide:tin nanopowders after heat treatment changed from white to yellow due to the substitution of oxygen vacancies in the sample. After calcination, the intensity of Raman peak significantly decreased with increasing amount of Sn loading. This phenomenon indicates that ion substitution may occur during the synthesis process. Moreover, it is noticed that the optical absorbance of obviously changed with increasing Sn loading.

scholarly journals Enhancement of GAD Storage Stability with Immobilization on PDA-Coated Superparamagnetic Magnetite Nanoparticles

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 969 ◽  
Author(s):  
Farheen Zafar ◽  
Hong-peng Wang ◽  
Chang-jiang Lv ◽  
Muhammad-Haseeb Ullah ◽  
Chun-yan Liu ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Storage Stability ◽  
Specific Activity ◽  
Precipitation Method ◽  
Acid Decarboxylase ◽  
Relative Specific Activity ◽  
Transmission Electron ◽  
Before And After ◽  
Co Precipitation ◽  
20 Nm

To improve the storage stability of glutamic acid decarboxylase (GAD), superparamagnetic magnetite (Fe3O4) nanoparticles were synthesized by co-precipitation method and coated with polydopamine (PDA) for GAD immobilization. Dynamic light scattering and transmission electron microscopy were used to determine size of the nanoparticles, which were approximately 10 nm, increasing to 15 nm after PDA-coating and to 20 nm upon GAD binding. Vibrational scanning measurements significantly represented the superparamagnetic behavior of the Fe3O4, and X-ray diffraction analysis confirmed that the crystalline structure before and after coating with PDA and the further immobilization of GAD remained the same. Thermogravimetric analysis and Fourier-transform infrared spectroscopy proved that the PDA-coating on Fe3O4 and further immobilization of GAD were successful. After immobilization, the enzyme can be used with a relative specific activity of 40.7% after five successive uses. The immobilized enzyme retained relative specific activity of about 50.5% after 15 days of storage at 4 °C, while free enzyme showed no relative specific activity after two days of storage. The GAD immobilization on PDA-coated magnetite nanoparticles was reported for the improvement of enzyme storage stability for the first time.

Effect of Doping Concentration on Grain Boundary Conductivity of Samaria Doped Ceria Composites

2021 ◽  
Author(s):  
Prerna Vinchhi ◽  
Roma Patel ◽  
Indrajit Mukhopadhyay ◽  
Abhijit Ray ◽  
Ranjan Pati
Keyword(s):  
Ionic Conductivity ◽  
Grain Boundary ◽  
Doping Concentration ◽  
Single Phase ◽  
Precipitation Method ◽  
Molecular Water ◽  
Doped Ceria ◽  
Boundary Conductivity ◽  
Co Precipitation ◽  
Hydrated Oxide

Abstract This work aims to study the effect of Sm3+ doping concentration on the grain boundary ionic conductivity of ceria. The materials were prepared by a modified co-precipitation method, where molecular water associated with the precursor has been utilized to facilitate the hydroxylation process. The synthesized hydroxide / hydrated oxide materials were calcined and the green body (pellet) has been sintered at high temperature in order to achieve highly dense (~ 96 %) pellet. The structural analyses were done using XRD and Raman spectroscopy, which confirm the single phase cubic structure of samaria doped ceria (SDC) nanoparticles and the surface morphology of sintered samples was studied using FESEM. The ionic conductivity was measured by AC impedance spectroscopy of the sintered pellets in the temperature range of 400-700 °C, which shows superior grain boundary conductivity. The grain boundary ionic conductivity of around 0.111 S/cm has been obtained for 15SDC composition at 600 °C.

Influence of the Synthesis Method on the Microstructure and the Electronic Paramagnetic Resonance in Manganite of Eu0.05Ca0.95MnO3

2011 ◽  
Vol 691 ◽  
pp. 139-144 ◽  
Author(s):  
M. Santiago T. ◽  
H. Montiel ◽  
L.E. Hernández C. ◽  
G. Álvarez ◽  
Maricela Villanueva-Ibáñez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Phase ◽  
Synthesis Method ◽  
Precipitation Method ◽  
Paramagnetic Resonance ◽  
Dc Magnetic Field ◽  
X Band ◽  
Preparation Route ◽  
Co Precipitation ◽  
Electron Paramagnetic

We present a comparison between co-precipitation method and polyol mediated synthesis for obtaining sub-micrometric powders of Eu0.05Ca0.95MnO3manganite. The samples synthesized were characterized by XRD and SEM; where the compounds have a single phase with the proposed stoichiometry. Microwave absorption response in poly-crystalline Eu0.05Ca0.95MnO3samples that it is carried out by both methods, are compared. These measurements were carried out at X-band (9.4 GHz) with a dc magnetic field up to 6000 Gauss, at 300 K. Electron Paramagnetic Resonance (EPR) spectra show important differences between both samples, indicating that the processes of magnetic absorption and the temperatures of phase transition are sensitive to order/disorder local; that we associate with the preparation route.

Structural and Magnetic Behavior of Cobalt Doped Ba0.5Sr0.5Fe12O19 Nanoparticles Synthesized by Chemical Co-Precipitation Technique

2013 ◽  
Vol 274 ◽  
pp. 406-410 ◽  
Author(s):  
Jun Li Zhang ◽  
Ze Wu ◽  
Li Min Dong ◽  
Tao Jiang ◽  
Xian You Zhang
Keyword(s):  
Saturation Magnetization ◽  
Barium Ferrite ◽  
Single Phase ◽  
Intermediate Phase ◽  
Cobalt Content ◽  
Magnetic Behavior ◽  
Precipitation Method ◽  
Vibrating Sample Magnetometer ◽  
Xrd Patterns ◽  
Co Precipitation

Nanocrystalline M-type Co2+ substituted barium hexaferrites samples having generic formula barium Ba0.5Sr0.5Fe12-xCoxO19 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were synthesized by chemical co-precipitation method. The sintered samples were characterized by XRD, SEM and VSM techniques. All the XRD patterns showed the single phase of the magnetoplumbite barium ferrite without other intermediate phase. The lattice parameters (a and c) obtained from XRD data decreases with increase in cobalt content x. The magnetic behavior of the samples was studied using vibrating sample magnetometer technique. The saturation magnetization (Ms) first increases reaching a maximum of 63.684 emu/g at x=0.4, and then decreases. The coercivity (Hc) decreases with increase in cobalt content x.

scholarly journals EVALUATION THE EFFECT OF NANOTECHNOLOGY ON PHARMACEUTICAL AND BIOLOGICAL PROPERTIES OF METRONIDAZOLE

2017 ◽  
Vol 9 (8) ◽  
pp. 139 ◽  
Author(s):  
Mustafa R. Abdulbaqi
Keyword(s):  
Drug Loading ◽  
In Vitro Release ◽  
Biological Properties ◽  
Precipitation Method ◽  
Diffusion Method ◽  
Biologic Activity ◽  
Before And After ◽  
Model Drug ◽  
Co Precipitation

Objective: This study aimed to evaluate the application of nanotechnology in improving the solubility and biologic activity as the antibacterial and antifungal drug of metronidazole (MTZ).Methods: Nanoparticles of bismuth sulfide (Bi2S3) were used as the nanocarriers for metronidazole (MTZ) and they were synthesized by chemical co-precipitation method. Drug loading on Bi2S3 nanoparticles, lattice property alteration and average particles sizes were evaluated using fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and powder X-ray diffraction (PXRD). The evaluation of the release of MTZ from Bi2S3 nanoparticles was carried out using USP type II rotating paddle apparatus. The antimicrobial activity of MTZ before and after loading was carried out by disc diffusion method against two aerobic gram+ve and one aerobic gram–ve bacteria, in addition to two fungi.Results: This study showed successful loading process as well as particles size reduction of MTZ after loading on Bi2S3 nanoparticles. In vitro release study showed a significant* increase in solubility and dissolution of MTZ after loading on Bi2S3 nanoparticles. MTZ showed a significant* increase in antibacterial (against gram+ve aerobic staphylococcus aureus and bacillus subtilis) and antifungal (Candida glabrata and Candida tropicalis) activities after loading process.Conclusion: Nanotechnology was applied successfully to improve both, solubility and biologic activity of the model drug used, metronidazole (MTZ). 

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